Tommy Flowers, an engineer at the Post Office Research Station in Dollis Hill, designs and builds Colossus from a plan by Max Newman to automate cryptanalysis of the Lorenz cipher (distinct from Enigma). Unlike Turing and Welchman's electromechanical Bombe, Colossus uses 1,500 thermionic valves to perform Boolean and counting operations at electronic speed, and is programmable via switches and plugboards to adapt to different cryptanalytic tasks. It enters service on 5 February 1944 at Bletchley Park. The concept that changes relative to the Bombe is not 'breaking ciphers' in general, but the architecture itself: it is the first computer that is simultaneously electronic (not electromechanical) and programmable.